package com.itstyle.seckill.topic.desinger.design_xw.observer;

import java.util.ArrayList;
import java.util.List;

/**
 * @Auther: liuwenxiang
 * @Date: 2019/9/18 23:36
 * @Description:
 */
//抽象目标：汇率
public abstract  class Rate {

    protected List<Company> list = new ArrayList<Company>();

    public void add(Company company)
    {
        list.add(company);
    }
    //删除观察者方法
    public void remove(Company company)
    {
        list.remove(company);
    }

    public abstract void change(int number);
}
